Orthopedic derotation devices and methods of installation thereof

ABSTRACT

Embodiments herein are generally directed to derotation systems, apparatuses, and components thereof that can be used in spinal derotation procedures, as well as methods of installation. The derotation systems may include a plurality of derotation towers and clamp members.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/015,770 which is a continuation of U.S. Ser. No. 15/598,572,filed May 18, 2017, which is a continuation application of U.S. Ser. No.14/665,273, filed Mar. 23, 2015, now U.S. Pat. No. 9,681,899, which arehereby incorporated by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present disclosure relates to orthopedic derotation devices andmethods used to install these devices.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. One general example of a spinal irregularityis an abnormal curvature of the spine, for example, as exhibited withscoliosis, kyphosis, and/or lordosis. Scoliosis, a side-to-sidecurvature of the spine, can affect the dimensions of an individual'schest area, thereby impacting performance of internal organs such as thelungs and heart.

Treatment of irregular spinal curvatures can include, for example,reducing the severity and preventing further progression of theirregularity through physical therapy, bracing, and/or surgery. Surgicalprocedures can include realigning or correcting the curvature of thespine and optionally placing one or more rods alongside thereof tomaintain the alignment.

SUMMARY OF THE INVENTION

Some embodiments herein are directed to a derotation system that caninclude first, second, and third derotation towers, wherein eachderotation tower comprises a proximal derotation tube coupled to adistal engagement assembly that is configured to engage an anchormember; first and second clamp members, wherein each clamp member isconfigured to receive at least two derotation tubes; and a handleassembly configured to engage one of the clamp members; wherein thefirst clamp member is configured to couple the first and secondderotation tubes along a first axis and the second clamp member isconfigured to couple the first and third derotation tubes along a secondaxis that is skewed relative to the first axis.

Other embodiments herein are directed to a derotation system that caninclude a plurality of derotation towers, wherein each derotation towercomprises a derotation tube; a plurality of clamp members each having alongitudinal axis, wherein each clamp member is configured to engage atleast two derotation tubes; and a handle assembly configured to engageone of the clamp members; wherein, when the clamp members are engagedwith the derotation tubes, the longitudinal axes of at least two clampmembers are skewed.

Yet other embodiments herein are directed to a derotation kit that caninclude a plurality of derotation towers, wherein each derotation towercomprises a proximal derotation tube; a plurality of clamp members,wherein each clamp member is configured to engage at least twoderotation tubes; a plurality of handle assemblies, wherein each handleassembly is configured to engage a clamp member; and a plurality ofcountertorque devices, wherein each countertorque device is configuredto engage at least one derotation apparatus.

Some embodiments herein are directed to a method of installing aderotation system that can include engaging a plurality of derotationtowers with a plurality of anchor members, wherein each derotation towercomprises a proximal derotation tube coupled to a distal engagementassembly; clamping a first clamp member around a first group of at leasttwo derotation tubes along a first axis; clamping a second clamp memberaround a second group of at least two derotation tubes along a secondaxis, wherein the second axis is skewed relative to the first axis;coupling a handle assembly to one of the first and second clamp members;and applying force to the handle assembly to adjust a position of atleast one derotation tower.

Other embodiments herein are directed to a method of installing aderotation system that can include engaging a plurality of derotationtowers with a plurality of anchor members to thereby push at least oneelongate rod into engagement with the anchor members, wherein eachderotation tower comprises a proximal derotation tube coupled to adistal engagement assembly; clamping a first clamp member around a firstgroup of at least two derotation tubes along a first axis; clamping asecond clamp member around a second group of at least two derotationtubes along a second axis, wherein the second axis is skewed relative tothe first axis; coupling a handle assembly to one of the first andsecond clamp members; and applying force to the handle assembly toadjust a position of at least one derotation tower.

Still other embodiments herein are directed to a method of installing aderotation system that can include providing a plurality of anchormembers and a plurality of derotation towers; engaging each derotationtower with a different anchor member; clamping each derotation tower toat least two other derotation towers along first and second axes thatare skewed relative to each other; and applying force to the system toadjust a position thereof.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating certain embodiments, are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of a derotation system asdescribed herein;

FIG. 2 illustrates a perspective view of a derotation tube and a distalengagement assembly as described herein;

FIG. 3 illustrates a perspective view of a clamp member and threederotation towers as described herein;

FIGS. 4A-B illustrate perspective views of derotation towers asdescribed herein;

FIG. 4C illustrates a cross-sectional view of the locking mechanism ofthe derotation tower illustrated in FIG. 4B;

FIG. 5A illustrates a perspective view of a derotation tower thatincludes a rod reducer assembly as described herein;

FIG. 5B illustrates the coupling mechanism of components of the rodreducer assembly illustrated in FIG. 5A;

FIGS. 5C-D illustrate perspective views of derotation towers that eachinclude a rod reducer assembly as described herein;

FIG. 6A illustrates a perspective view of a clamp member as describedherein;

FIGS. 6B-D illustrate perspective views of a clamp member transitioningfrom an unlocked to a locked configuration as described herein;

FIG. 7 illustrates a perspective view of a handle assembly coupled to aclamp member and a countertorque device coupled to a derotation tower asdescribed herein;

FIG. 8 illustrates a handle assembly as described herein;

FIG. 9 illustrates a countertorque device as described herein; and

FIG. 10 illustrates a perspective view of an alternative clamp member.

DETAILED DESCRIPTION

In some procedures to treat irregular spinal curvatures, a surgeon orother user may attach bone anchors to select vertebrae of the spine. Arod can be inserted through the bone anchors to adjust or maintain therelative positions of the vertebrae, thereby promoting correction of thecurvature. A mechanical force can be used to deliver the rod to the boneanchors in a process that may be referred to as reduction. In someinstances, a locking member, such as a set screw or locking cap, can becoupled with the bone anchor to retain the rod therein. In addition toadjusting for curvature, the angular rotation of one or more vertebraerelative to other vertebrae can be adjusted. This process can involverotating the anchors and/or rods via tube members and can be referred toas derotation. Accordingly, described herein are derotation systems andcomponents thereof that can be advantageously used to manipulate and/oradjust the rotational angle of one or more vertebrae.

Components of all of the systems and devices disclosed herein can bemade of materials known to those skilled in the art, including metals(e.g., titanium), metal alloys (e.g., stainless steel, titanium alloys,and/or cobalt-chromium alloys), ceramics, polymers (e.g., poly etherether ketone (PEEK), polyphenylene sulfone (PPSU), polysulfone (PSU),polycarbonate (PC), polyetherimide (PEI), polypropylene (PP),polyacetals, or mixtures or co-polymers thereof), allograft, and/orcombinations thereof. In some embodiments, the systems and devices mayinclude radiolucent and/or radiopaque materials. In some embodiments,the systems and devices may be formed of silicone rubber. In otherembodiments, one or more components may be coated with a bonegrowth-enhancing material, such as hydroxyapatite. The components canalso be machined and/or manufactured using techniques known to thoseskilled in the art. For example, polymeric components may beinjection-molded or blow-molded.

Embodiments herein are directed to derotation systems that can includeone or more derotation towers and/or clamp members. The clamp membersmay be configured to couple, clamp, and/or link the derotation towerstogether to form the derotation system. In some embodiments, thederotation systems can additionally include one or more handleassemblies and/or countertorque devices. Advantageously, those skilledin the art may appreciate that the derotation systems of the presentdisclosure may include any combination of any embodiments of derotationtowers, clamp members, handle assemblies, and/or countertorque devicesdescribed herein. The derotation systems may be configured to adjust thecurvature and/or rotation of a patient's spine in a derotationprocedure, as described herein. In some embodiments, the derotationsystems may also be configured to reduce a rod, e.g., to push a rod intoengagement with an anchor member, such as a tulip head or pedicle screw.The derotation towers may advantageously be cannulated to allow passageof a fastener, such as a set screw or locking cap, therethrough. In use,after the spine is derotated, the fastener may be passed through thederotation tower to couple with an anchor member, thereby securing theanchor member to a rod and/or at a particular angle.

The derotation towers described herein can each include a proximalderotation tube coupled to and/or extending from a distal engagementassembly. The derotation tube can include a longitudinal axis and avariable (e.g., angled, non-smooth, abrasive, roughened,increased-friction, coarse, grainy, sandblasted, knurled, texturized,bumpy, ridged, toothed, and/or irregular) transverse (e.g.,circumferential) outer surface thereabout. The derotation tube caninclude a cannula extending entirely therethrough along the longitudinalaxis thereof. The longitudinal axis can be a straight or curved line.The distal engagement assembly can be configured to engage an anchormember (e.g., a bone anchor such as a pedicle screw or hook, alone or incombination with a housing, such as a tulip head, and/or an elongaterod). The systems disclosed herein can include a plurality of derotationtowers, e.g., 2, 3, 4, 5, 6, 7, 8, or more towers. In some embodiments,the systems disclosed herein can include at least first, second, andthird derotation towers.

Turning now to FIG. 1, some embodiments herein are directed to aderotation system 100 that can include one or more derotation towers,such as derotation tower 2, and one or more clamp members, such as clampmember 4. As illustrated in FIG. 2, derotation tower 2 can include aproximal derotation tube 6 and a distal engagement assembly 8. Theproximal derotation tube 6 can include a longitudinal axis 9 and avariable transverse outer surface thereabout. As illustrated in FIG. 2,the derotation tube 6 can include a plurality of angled surfaces 10. Insome embodiments, the derotation tube 6 can include six angled surfaces(e.g., can include a hexagonal outer surface or transverse outercross-section). In other embodiments, the derotation tube 6 can include3, 4, 5, 6, 7, 8 or more angled surfaces. In some embodiments, thederotation tube 6 can include first and second rotatable members 12, 14.The first and second rotatable members 12, 14 can be positioned inseries along the longitudinal axis 9. Each of the first and secondrotatable members 12, 14 can include a variable outer surface. Forexample, each of the first and second rotatable members 12, 14 caninclude a hexagonal outer surface or transverse outer cross-section. Thefirst and second rotatable members 12, 14 may be advantageouslyconfigured to rotate relative to each other. In some embodiments, thederotation tube 6 can further include a locking member configured tolock the rotational orientation of the first and/or second rotatablemembers 12, 14. Advantageously, the first and second rotatable members12, 14 can be configured to each couple to a clamp member along adifferent axis, as illustrated in FIG. 1. Each rotatable member 12, 14can be rotated individually to adjust and/or accommodate the orientationof the clamp member.

An alternative embodiment of a proximal derotation tube is proximalderotation tube 16, illustrated in FIG. 3. Derotation tube 16 caninclude a longitudinal axis 18 and a variable transverse outer surfacethereabout. In these embodiments, derotation tube 16 may be a unitary(e.g., one-piece) tube. As illustrated in FIG. 3, at least a section ofthe variable transverse outer surface of the derotation tube 16 caninclude roughening and/or texturizing (e.g., knurling). In someembodiments, derotation tube 16 may be referred to as a knurled tube.

In some embodiments, the proximal derotation tube and the distalengagement assembly, or a component thereof, may form a unitary body. Inother embodiments, the proximal derotation tube may be reversibly orirreversibly coupled to the distal engagement assembly. For example, insome embodiments the proximal derotation tube may be welded to thedistal engagement assembly. In other embodiments, the proximalderotation tube may be clipped, threaded, snapped, bolted, and/orotherwise coupled to the distal engagement assembly. In embodimentswhere the distal engagement assembly includes two or more components(e.g., an inner sheath and an outer sheath), the proximal derotationtube may be coupled with any of the components.

One embodiment of a distal engagement assembly, distal engagementassembly 20, is illustrated in FIG. 4A. The distal engagement assembly20 can include an outer sleeve 22 slideably disposed over an innersleeve 24. The inner sleeve 24 can include a distal end 26 configured toengage an anchor member 28. As illustrated in FIG. 4A, the distal end 26of the inner sleeve 24 can include two tips 30, 32 separated by alongitudinal slot 34. Each tip 30, 32 may also include a beveledprotrusion (not shown) extending radially outwards and that may beconfigured to engage an inner surface of the outer sleeve 22.

The outer sleeve 22 may include a channel 38 at a proximal end having anenlarged proximal opening 34 and an enlarged distal opening 36. Theproximal opening 34 and the distal opening 36 may each have a width thatis greater than that of an intermediate portion 35 therebetween. Forexample, the channel 38 may be generally “I”-shaped. As illustrated inFIG. 4A, the channel 38 may pass entirely through the outer sleeve 22 ina transverse direction. In some embodiments, the proximal end of theouter sleeve 22 may also include one, two, or more flat exteriorsections. In some embodiments, the outer sleeve 22 can include twoparallel flat exterior sections (e.g., two parallel walls). The flatexterior sections may be configured to couple with one or moreinstallation tools, such as a countertorque device, described furtherherein.

The distal engagement assembly 20 can also include an actuator 40.Actuator 40 may be coupled to a stop 42. The stop 42 may be sized to fitwithin the enlarged proximal and distal openings 34, 36, but not withinthe intermediate portion 35. In use, when the actuator 40 is depressed,the distal engagement assembly 20 may transition between an unlockedposition and a locked position, wherein in the locked position thedistal engagement assembly 20 is coupled (e.g., secured) to and/orengaged with the anchor member 28. In the locked position, illustratedin FIG. 4A, the stop 42 may be positioned within the proximal opening 34and the outer sleeve 22 may engage the beveled protrusion (not shown) oneach tip 30, 32. In this position, the outer sleeve 22 may be applying aradial force on the beveled protrusions, causing the slot 34 tocompress, bringing the tips 30, 32 together to clamp the anchor member28 therebetween. To transition to the unlocked position, e.g., todisengage the distal engagement assembly 20 from the anchor member 28,the actuator 40 may be depressed (e.g., squeezed), disengaging the stop42 from the proximal opening 34. The outer sleeve 22 may then betranslated proximally until the beveled protrusions are uncovered andthe stop 42 is aligned with the distal opening 36. The actuator 40 maythen be released to allow the stop 42 to be retained within the distalopening 36. To transition to the locked position, e.g., to engage thedistal engagement assembly 20 with the anchor member 28, the actuator 40may be depressed (e.g., squeezed), disengaging the stop 42 from thedistal opening 36. The outer sleeve 22 may then be translated distallyuntil the beveled protrusions are covered and the stop 42 is alignedwith the proximal opening 34. The actuator 40 may then be released toallow the stop 42 to be retained within the proximal opening 34.

Another embodiment of a distal engagement assembly, distal engagementassembly 44, is illustrated in FIGS. 4B-C. The distal engagementassembly 44 can include an outer sleeve 46 slideably disposed over aninner sleeve 48. The inner sleeve 48 can include a distal end 50configured to engage an anchor member (not shown). As illustrated inFIG. 4B, the distal end 50 of the inner sleeve 48 can include two tips52, 54 separated by a longitudinal slot 56. Each tip 52, 54 may alsoinclude a protrusion 58, 60 extending radially outwards and that may beconfigured to engage an inner surface of the outer sleeve 46. The innersleeve 48 may also include a proximal end 62, illustrated in FIG. 4C.The proximal end 62 may include a circumferential groove 64 on an outersurface thereof. The circumferential groove 64 may be configured toreceive a retaining ring 66 therein. As illustrated in FIG. 4C, theretaining ring 66 may be configured to be disposed between the innersleeve 48 and the outer sleeve 46. In some embodiments, the retainingring 66 may be compressible and/or compliant.

The outer sleeve 46 may include a distal end 68 and a proximal end 70,as illustrated in FIGS. 4B-C. The distal end 68 may be configured toengage the protrusions 58, 60 of the inner sleeve 48. The proximal end70 may include a distal circumferential groove 72 and a proximalcircumferential groove 74, both extending along an inner surfacethereof. As illustrated in FIG. 4B, the proximal end 70 may also includeat least one or more concave gripping surfaces 76, 78. Each concavegripping surface 76, 78 may include an engagement or friction-increasingfeature, such as ridges, teeth, knurling, and/or sandblasting. In someembodiments, the proximal end 70 may also include one, two, or more flatexterior sections. In some embodiments, the proximal end 70 can includetwo parallel flat exterior sections (e.g., two parallel walls). The flatexterior sections may be configured to couple with one or moreinstallation tools, such as a countertorque device, described furtherherein.

In use, the distal engagement assembly 44 may transition between anunlocked position and a locked position, wherein in the locked positionthe distal engagement assembly 44 is coupled (e.g., secured) to and/orengaged with an anchor member (not shown). Although not illustrated,those skilled in the art may appreciate that an anchor member (e.g., abone screw engaged with a housing and/or a rod) may be positionedbetween the tips 52, 54 prior to transitioning the distal engagementassembly from the unlocked position to the locked position. In theunlocked position, illustrated in FIG. 4B-C, the protrusions 58, 60 atthe distal end 50 of the inner sleeve 48 may be exposed (e.g., notengaged with the outer sleeve 46). Additionally, the retaining ring 66may rest within the groove 64 on the proximal end 62 of the inner sleeve48 and the distal groove 72 on the proximal end 70 of the outer sleeve46. In some embodiments, the groove can be circumferential orrectangular. The retaining ring 66 may inhibit the outer sleeve 46 fromtranslating axially. To transition to the locked position, e.g., toengage the distal engagement assembly 44 with the anchor member, a usermay grasp the concave gripping surfaces 76, 78 and translate or slidethe outer sleeve 46 distally. The retaining ring 66 may be pushed and/orcompressed into the circumferential groove 64, allowing the outer sleeve46 to translate or slide. The outer sleeve 46 may continue to translatedistally until the retaining ring 66 is aligned with the proximal groove74 and the distal end 68 of the outer sleeve 46 has engaged theprotrusions 58, 60. When the retaining ring 66 is aligned with theproximal groove 74, it may move and/or expand into the proximal groove74, thereby inhibiting the outer sleeve 46 from translating axially. Inthis position, the distal end 68 of the outer sleeve 46 may be applyinga radial force on the protrusions 58, 60, causing the slot 56 tocompress, bringing the tips 52, 54 together to clamp the anchor member(not shown) therebetween.

In some embodiments, the distal engagement assembly may include a rodreducer assembly which be configured to reduce a rod engaged with ananchor member (e.g., may be configured to urge a rod towards the anchormember or portion thereof). Some embodiments may include rod reducerassembly 80, illustrated in FIG. 5A. Rod reducer assembly 80 may includea connector member 82 and a clip reducer 84 configured to be reversiblycoupled with the connector member 82. The rod reducer assembly 80 mayalso include a threaded driver (not shown).

The connector member 82 may be a generally tubular body having a cannulaextending longitudinally therethrough. The connector member 82 mayinclude a proximal end 83 that is coupled to the derotation tube 16. Theproximal end 83 may also include a collar 96. The collar 96 may begenerally cylindrical with two flat exterior sections 94, 95 (e.g., twoparallel walls). The flat exterior sections 94, 95 may be configured tocouple with one or more installation tools, such as a countertorquedevice, described further herein. The connector member 82 may include afirst cantilevered tab 86 and a symmetrical second cantilevered tab 88on an opposite side of the connector member 82, as illustrated in FIG.5B. The tabs may protrude radially outward from an outer surface of theconnector member 82 as well as inward from an inner surface thereof. Asillustrated in FIG. 5A, rod reducer assembly 80 may also include ahandle member 90 having a cannula extending longitudinally therethroughand two arms 92, 93 extending transversely therefrom. The connectormember 82 may be received within the cannula of the handle member 90.The handle member 90 may have an inner surface configured to engage anouter surface of the tabs 86, 88. The handle member 90 may be coupled tothe proximal end 83 of the connector member 82 by a spring member 97,such as a compression spring.

The clip reducer 84 may be cannulated and may include a distal end 98configured to engage anchor member 28. As illustrated in FIG. 5A, thedistal end 98 can include two tips 104, 106 separated by a longitudinalslot 108. The clip reducer 84 may be configured to receive the anchormember 28 between the two tips 104, 106. Each tip 104, 106 may alsoinclude a protrusion (not shown) extending radially outwards and thatmay be configured to engage an inner surface of a reduction member 102.The reduction member 102 may be slideably engaged with the clip reducer84. The reduction member 102 may be a tubular member having a cannulaextending therethrough, and may include a distally-extending tip 110. Insome embodiments, the reduction member 102 may be generally chevron- orV-shaped when viewed from a side. The tip 110 may include apartially-circular (e.g., concave) cut-out configured to engage, nest,or abut a cylindrical rod. The clip reducer 84 may be received withinthe cannula of the reduction member 102. The reduction member 102 may beconfigured to slide longitudinally (e.g., distally and/or proximally)along the clip reducer 84. The clip reducer 84 may also include aproximal end 112, as illustrated in FIG. 5B. The proximal end 112 mayinclude depressions or recesses 114, 116 that can be configured toreceive at least a portion of tabs 86, 88 therein. The rod reducerassembly 80 may further include an elongate threaded driver (not shown).The driver may be configured to engage and/or actuate the reductionmember 102.

In use, the connector member 82 may be coupled with the clip reducer 84as follows. The arms 92, 93 of the handle member 90 may be grasped andthe handle member 90 pulled proximally towards the collar 96 to compressthe spring member 97 and release the tabs 86, 88. The proximal end 112of the clip reducer 84 may be inserted into a distal end of theconnector member 82 until the recesses 114, 116 are aligned with thetabs 86, 88. The arms 92 of the handle member 90 may then be released,thereby releasing the spring member 96 and causing the handle 90 toreturn to its distal position. The inner surface of the handle 90 mayengage the tabs 86, 88, pushing them radially inwards and into therecesses 114, 116. The handle 90 may retain the tabs 86, 88 within therecesses 114, 116 and may thereby inhibit the connector member 82 fromdisengaging from the clip reducer 84.

To engage rod reducer assembly 80 with an anchor member, the distal end98 of the clip reducer 84 may be positioned or placed around at least aportion of the anchor member 28. The clip reducer 84 may be placedaround anchor member 28 before or after coupling with the connectormember 82. Although not illustrated in FIG. 5A, those skilled in the artmay appreciate that, in use, anchor member 28 may include an elongaterod resting in the U-shaped opening thereof. To reduce the rod, e.g., tourge the rod into closer and/or secure engagement with the anchor member28, the threaded driver or screw may be threaded through the clipreducer 84. Rotation of the threaded driver, which is in engagement withthe reduction member 102, can cause the reduction member 102 totranslate distally. As the reduction member 102 translates distally, itmay apply a radial force on the tips 104, 106, compressing the slot 108and causing the tips 104, 106 to clamp the anchor member 28therebetween. The threaded driver may urge the reduction member 102 totranslate distally until it abuts the elongate rod (not shown) and urgesor pushes the elongate rod into engagement with the anchor member 28.

FIG. 5C illustrates another embodiment of a rod reducer assembly. Rodreducer assembly 118 may include a clip reducer 120 and a threadeddriver 122. The clip reducer 120 can include a proximal end 124 and adistal end 126. The clip reducer 120 may be coupled to derotation tube16 at the proximal end 124. The proximal end 124 may also include one,two, or more flat exterior sections 138. In some embodiments, theproximal end 124 can include two parallel flat exterior sections (e.g.,two parallel walls). The flat exterior sections 138 may be configured tocouple with one or more installation tools, such as a countertorquedevice, described further herein. The distal end 126 may include twotips 128, 130 separated by a longitudinal slot 132. The rod reducerassembly 118 may also include a reduction member 134 that is slideablyengaged with the clip reducer 120. The reduction member 134 may be atubular member having a cannula extending therethrough, and may includea distally-extending tip 136. In some embodiments, the reduction member134 may be generally chevron- or V-shaped when viewed from a side. Thetip 136 may include a partially-circular (e.g., concave) cut-outconfigured to engage or abut a cylindrical rod. The clip reducer 120 maybe received within the cannula of the reduction member 134. Thereduction member 134 may be configured to translate or slidelongitudinally (e.g., distally and/or proximally) along the clip reducer120.

The threaded driver 122 may be configured to be received within thecannula of the clip reducer 120 and may be configured to engage thereduction member 134. To engage rod reducer assembly 118 with an anchormember, the distal end 126 or a portion thereof may be placed orpositioned around an anchor member. In use, the tips 128, 130 may beplaced around an anchor member that may include, for example, a housingand a fastener (e.g., a pedicle screw or hook) therein. An elongate rodmay also be placed or positioned at or within the housing. To reduce therod, e.g., to urge the rod into closer engagement with the anchormember, the threaded driver 122 may be inserted (e.g., threaded) throughthe clip reducer 120 from a proximal end of the derotation tube 16 andinto engagement with the reduction member 134. The threaded driver 122may actuate the reduction member 134, causing it to translate distally.As the reduction member 134 translates distally, it may apply a radialforce on the tips 128, 130, compressing the slot 132 and causing thetips 128, 130 to clamp the anchor member therebetween. The threadeddriver 122 may urge the reduction member 134 to translate distally untilit abuts the elongate rod (not shown) and urges or pushes the elongaterod into engagement with the anchor member.

FIG. 5D illustrates another embodiment of a rod reduction assembly. Rodreduction assembly 140 can include an inner sleeve 142, an outer sleeve144, and a rotatable handle 146. The inner sleeve 142 may include aproximal end 148 and a distal end 150. The proximal end 148 may beconfigured to couple with derotation tube 16. The inner sleeve 142 maybe configured to engage anchor member 28. In some embodiments, thedistal end 150 can include two or more tips 152, 154 (e.g., four ormore) separated by a longitudinal slot 156. The inner sleeve 142 may beconfigured to receive the anchor member 28 between the two tips 152,154. Each tip 152, 154 may also include a protrusion (not shown)extending radially outwards and that may be configured to engage aninner surface of the outer sleeve 144.

The outer sleeve 144 may be slideably disposed over the inner sleeve 142and may be configured to reduce an elongate rod (not shown). The outersleeve 144 may include a proximal end 158 and a distal end 160. Thedistal end 160 may include a distal tip 162 having a partially-circular(e.g., concave) cut-out configured to engage, nest, or abut acylindrical rod. The proximal end 158 may include one, two, or more flatexterior sections. In some embodiments, the proximal end 158 can includetwo parallel flat exterior sections (e.g., two parallel walls). The flatexterior sections may be configured to couple with one or moreinstallation tools, such as a countertorque device, described furtherherein. The proximal end 158 may be engaged or coupled with therotatable handle 146. The rotatable handle 146 may be configured toactuate the outer sleeve 144.

To engage rod reducer assembly 140 with anchor member 28, the distal end150 or a portion thereof may be placed or positioned around the anchormember 28. In use, the tips 152, 154 may be placed around anchor member28 (e.g., a tulip head or other housing). Although not illustrated inFIG. 5D, those skilled in the art may appreciate that, in use, anchormember 28 may include an elongate rod resting in the U-shaped openingthereof. To reduce the rod, e.g., to urge the rod into closer and/orsecure engagement with the anchor member 28, the rotatable handle 146may be rotated (e.g., threaded onto the inner sleeve 142) to actuate theouter sleeve 144, thereby urging and/or pushing the outer sleeve 144 ina distal direction. As the outer sleeve 144 translates distally, it mayapply a radial force on the tips 152, 154, compressing the slot 156 andcausing the tips 152, 154 to clamp the anchor member 28 therebetween.The rotatable handle 146 may continue to rotate, urging the outer sleeve144 to translate distally until it abuts the elongate rod (not shown)and urges or pushes the elongate rod into engagement with the anchormember 28.

The derotation systems disclosed herein may also include first, second,or more clamp members. In some embodiments, each clamp member may beconfigured to engage, couple, and/or receive (e.g., clamp) at least twoderotation towers or portions thereof (e.g., proximal derotation tubeand/or distal engagement assembly). For example, each clamp member maybe configured to engage, couple, and/or receive (e.g., clamp) at leasttwo derotation tubes. Thus, the derotation systems described herein mayinclude a plurality of clamp members and derotation tubes. Anycombination of embodiments of clamp members, derotation towers, and/orderotation tubes may be used in the derotation systems described herein.In some embodiments that include a plurality of (e.g., two or more)clamp members engaged with a plurality of derotation tubes, thelongitudinal axes of at least two clamp members may be skewed (e.g., thelongitudinal axes would intersect if in the same plane). In someembodiments, the derotation system can include at least three (e.g.,first, second, and third) derotation towers and at least two (e.g.,first and second) clamp members. In these embodiments, the first clampmember may be configured to couple two (e.g., first and second)derotation tubes along a first axis and the second clamp member may beconfigured to couple two (e.g., first and third) derotation tubes alonga second axis, wherein the second axis is skewed relative to the firstaxis (e.g., the first and second axes would intersect if in the sameplane). In other embodiments, the clamp members may be configured toengage each derotation tower in the system with at least a firstadjacent derotation tower along a first axis and at least a secondadjacent derotation tower along a second axis, wherein the second axisis skewed relative to the first axis. One such example is illustrated inFIG. 1.

FIG. 6A illustrates one embodiment of a clamp member. Clamp member 164can include a first elongate arm 166 and a second elongate arm 168. Thefirst elongate arm 166 can be coupled to an actuator assembly 170 andthe second elongate arm can include a receiving portion 172 extendingtherefrom. Clamp member 164 can also include a first end 174 and asecond end 188, wherein the first and second arms 166, 168 may becoupled together at the first end 174. Clamp member 164 may include alongitudinal axis that extends between the first and second ends 174,188.

The first arm 166 can include an inner surface 184 and an outer surface186, wherein the inner surface 184 is closer to the second arm 168 andthe outer surface 186 is farther from the second arm 168. As illustratedin FIG. 6A, the term “inner surface” can refer to a surface attached tothe first arm 166, as well as to the direct surface of the first arm166. The inner surface 184 can advantageously include a retaining (e.g.,friction-increasing) feature. In some embodiments, the inner surface 184may include a variable surface feature, and may be, for example, angled,non-smooth, abrasive, roughened, increased-friction, coarse, grainy,sandblasted, knurled, texturized, bumpy, ridged, toothed, and/orirregular. As illustrated in FIG. 6A, the retaining feature of the innersurface 184 can include knurling. In other embodiments, the retainingfeature may be soft, compressive, and/or compliant. For example, theretaining feature may be a polymeric (e.g., silicone) surface. In yetother embodiments, the retaining feature can include a scallopedsurface, e.g., a plurality of indentations, wherein each indentation isconfigured to nest a portion of a derotation apparatus therein. Thesecond arm 168 can also have an inner surface having some or all of thesame features as the inner surface 184. As illustrated with respect tothe second arm 168, in some embodiments the outer surface of either orboth arms can include a plurality of curved depressions or indentations192.

The first and second elongate arms 166, 168 may be pivotably coupled atthe first end 174 of the clamp member 164. The first and second elongatearms 166, 168 may also be coupled to a spring member, such as acantilever or torsion spring, at the first end 174. Thus, in use, whenthe arms 166, 168 are pulled apart and subsequently released, the springmember may pull the arms 166, 168 back towards each other.

The receiving portion 172 can include a receptacle 176 therein. At leasta portion of the actuator assembly 170 may be configured to bereversibly received within the receptacle 176. In some embodiments, thereceptacle 176 can be open on one side and can be, for example, aU-shaped channel or opening. In other embodiments, the receptacle may bea forked opening (e.g., may include two tines defining a channeltherebetween). In yet other embodiments, the receptacle can include atapered opening, e.g., such that the width of the opening of thereceptacle is less than the diameter of the receptacle. In someembodiments, the receptacle 176 may have a constant diameter or width asmeasured longitudinally from the inner surface to the outer surface ofthe second arm 168. For example, the receptacle 176 may generally havethe shape of a cylindrical segment. In other embodiments, the receptacle176 may have a variable diameter or width. For example, the receptacle176 may be tapered (e.g., conical or frustoconical). In someembodiments, the receptacle 176 can include a countersink configured tonest a portion of the actuator assembly 170 (e.g., head member 182)therein.

The actuator assembly 170 can include a threaded rod 178 and a threadednut 180. The threaded nut 180 can be generally cylindrical and caninclude a threaded passageway configured to mate with the threaded rod178. In some embodiments, the threaded nut 180 can include a grippingsurface. For example, as illustrated in FIG. 6A, the threaded nut 180can be texturized and can include a plurality of alternating ridges andvalleys. In some embodiments, the threaded nut 180 can be coupled to ahead member 182. The head member 182 can be configured to be received(e.g., locked) within the receptacle 176. The head member 182 may beconfigured to rotate within the receptacle 176.

In some embodiments, the head member 182 may be distal to the threadednut 180, as illustrated in FIG. 6A. In other embodiments, for example,as illustrated in FIG. 1, clamp member 165 may include a threaded nut181 that is distal to the head member 183. Those skilled in the art mayappreciate that, except as otherwise described herein, clamp member 165may include the same features as clamp member 164. FIG. 10 shows analternative embodiment of an assembly whereby the threaded nut 180 ispositioned on an outer surface of the actuator assembly 170.

In some embodiments, the actuator assembly 170 may be pivotably coupledto the first elongate arm 166, for example, at the second end 188 of theclamp member 164. The actuator assembly 170 may be configured to pivotabout a pin 190, and in some embodiments, may be configured to pivot byapproximately 90 degrees relative to the first elongate arm 166. Theactuator assembly 170 may be configured to pivot between a closedposition and an open position. In the closed position, the actuatorassembly 170 may be generally perpendicular to the first elongate arm166, and/or at least a portion of the actuator assembly 170 may bereceived within the receptacle 176. In some embodiments, in the closedposition, the threaded nut 180 may be configured to be received betweenthe first and second elongate arms 166, 168. In other embodiments, forexample, as illustrated in FIG. 1, when in the closed position, thethreaded nut 181 may be configured to be outside of both the first andsecond elongate arms 167, 169. In the open position, the actuatorassembly 170 may be generally parallel to the first elongate arm 166. Insome embodiments, the clamp member 164 may further include a springmember, such as a cantilever or torsion spring, that may be coupled tothe first elongate arm 166 and the actuator assembly 170. In use, whenthe actuator assembly 170 is pulled or urged to the open position andreleased, the spring member may apply force on the actuator assembly 170to pivot or return the actuator assembly 170 towards the closed position(e.g., towards the receptacle 176, relative to the first elongate arm166).

The clamp member 164 may be configured to clamp, couple, engage, and/orsecure at least two derotation towers. In use, the clamp member 164 maybe pulled open by pivoting the actuator assembly 170 to the openposition and pulling, urging, and/or pivoting the first and second arms166, 168 apart. The clamp member 164 may then be placed around at leasttwo derotation towers (e.g., around two or more proximal derotationtubes). For example, the at least two derotation tubes may be placedbetween the first and second arms 166, 168. Advantageously, theretaining surfaces on the derotation tubes and/or inner surfaces of thefirst and second arms 166, 168 may retain or increase friction betweenthe members. The first and second arms 166, 168 may be brought togetherand the actuator assembly 170 may be pivoted towards the receptacle 176to the closed position, with at least a portion of the actuator assembly170 (e.g., the head member 182) inserted into and/or received within thereceptacle 176. The derotation towers may be clamped within the clampmember 164 by threading the nut 180 along the rod 178. The head member182, which may be captured within the receptacle 176 of the second arm168, may urge the second arm 168 towards the first arm 166 to reduce adistance between the first and second arms 166, 168 at the second end188 of the clamp member 164. The head member 182 may rest within acountersink of the receptacle 176, thereby inhibiting the second arm 168from being released.

Turning to FIGS. 6B-D, an alternative embodiment of a clamp member isillustrated. Clamp member 194 can include a first elongate arm 196 and asecond elongate arm 198. The first elongate arm 196 can be coupled to anactuator assembly 202 and the second elongate arm can include areceiving portion 204 extending therefrom. Clamp member 194 can alsoinclude a first end 206 and a second end 208. The first and second arms196, 198 may be coupled together at the first end 206, for example, by ahinge member 207. Clamp member 194 may include a longitudinal axis thatextends between the first and second ends 206, 208.

The first arm 196 can include an inner surface 210 and an outer surface212, wherein the inner surface 210 is closer to the second arm 198 andthe outer surface is farther from the second arm 198. The term “innersurface” can refer to a surface attached to the first arm 196, as wellas to the direct surface of the first arm 196. The inner surface 210 canadvantageously include a retaining (e.g., friction-increasing) feature.In some embodiments, the inner surface 210 may include a variablesurface feature, and may be, for example, angled, non-smooth, abrasive,roughened, increased-friction, coarse, grainy, sandblasted, knurled,texturized, bumpy, ridged, toothed, and/or irregular. In otherembodiments, the retaining feature may be soft, compressive, and/orcompliant. For example, the retaining feature may be a polymeric (e.g.,silicone) surface. In yet other embodiments, the retaining feature caninclude a scalloped surface, e.g., a plurality of indentations, whereineach indentation is configured to nest a portion of a derotationapparatus therein, as illustrated in FIGS. 6B-D. The second arm 198 canalso have an inner surface having some or all of the same features asthe inner surface 210. In some embodiments, the outer surface of thefirst and/or second arms may also include a retaining feature. Forexample, in some embodiments the outer surface of either or both armscan include a plurality of curved depressions or indentations (notshown).

The first and second elongate arms 196, 198 may be pivotably coupled atthe first end 202 of the clamp member 194. The first and second elongatearms 196, 198 may also be coupled to a spring member, such as acantilever or torsion spring, at the first end 206. Thus, in use, whenthe arms 196, 198 are pulled apart and subsequently released, the springmember may pull the arms 196, 198 back towards each other.

As illustrated in FIGS. 6B-D, the receiving portion 204 may extend at anoblique angle (e.g., greater than 90 degrees) relative to the secondelongate arm 198. In other embodiments, the receiving portion 204 may beperpendicular to the second elongate arm 198. The receiving portion 204can include a receptacle 214 therein. At least a portion of the actuatorassembly 202 may be configured to be reversibly received within thereceptacle 214. As illustrated in FIG. 6B, the receptacle 214 can beopen on one side and can be, for example, a U-shaped channel or opening.In other embodiments, the receptacle may be a forked opening (e.g., mayinclude two tines defining a channel therebetween). In yet otherembodiments, the receptacle can include a tapered opening, e.g., suchthat the width of the opening of the receptacle is less than thediameter of the receptacle. In some embodiments, the receptacle 214 mayhave a constant diameter or width as measured longitudinally from theinner surface to the outer surface of the second arm 198. In otherembodiments, the receptacle 214 may have a variable diameter or width.For example, the receptacle 214 may be tapered (e.g., conical orfrustoconical). In some embodiments, the receptacle 214 can include acountersink configured to nest a portion of the actuator assembly 202(e.g., nut 218) therein.

The actuator assembly 202 can include a threaded rod 216 and a threadednut 218. The threaded nut 218 can be generally cylindrical and caninclude a threaded passageway configured to mate with the threaded rod216. In some embodiments, the threaded nut 218 can include a grippingsurface, such as a plurality of alternating ridges and valleys. Asillustrated in FIGS. 6B-D, the threaded nut 218 can include two grippingwings, and may be referred to as a wing nut. In some embodiments, thethreaded nut 218 can be coupled to a head member (not shown), asdescribed herein with respect to clamp member 164.

As illustrated in FIGS. 6B-D, the threaded rod 216 may be coupled (e.g.,affixed, connected, and/or attached) to the first arm 196. The threadedrod 216 may have an axis that is generally parallel to a length of thefirst arm 196. The threaded rod 216 may have a length that is greaterthan a width of the second arm 198. As described herein, the threadedrod 216 may be configured to be reversibly received within thereceptacle 214 of the second arm 198.

The clamp member 194 may be configured to clamp, couple, engage, and/orsecure at least two derotation towers. In use, the first and second arms196, 198 may be pulled, urged, and/or pivoted apart and placed aroundtwo or more derotation towers (e.g., around two or more proximalderotation tubes), as illustrated in FIG. 6B. For example, the at leasttwo derotation tubes may be placed between the first and second arms196, 198. Advantageously, the derotation tubes may nest within and/oragainst the scalloped features on the inner surfaces of the first andsecond arms 196, 198. The first and second arms 196, 198 may be broughttogether so that the threaded rod 216 of the first arm 196 is receivedwithin the receptacle 214 of the second arm 198, as illustrated in FIG.6C. The derotation towers may be clamped within the clamp member 194 bythreading the nut 218 along the rod 216 towards the first end 206 of theclamp member 194, as illustrated in FIG. 6D. As the nut 218 moves alongthe rod 216, it may exert pressure on the receiving portion 204. Inembodiments where the receiving portion 204 is obliquely angled,applying pressure on the receiving portion 204 may cause the second arm198 to pivot towards the first arm 196, thereby clamping the derotationtowers therebetween and/or reducing a distance between the first andsecond arms 196, 198 at the second end 208 of the clamp member 194. Thethreaded nut 218 may nest within a countersink of the receptacle 214,thereby inhibiting the second arm 198 from being released.

Derotation systems described herein may also include a handle assembly300, as illustrated in FIGS. 7-8. The handle assembly 300 may beconfigured to engage or couple with any of the clamp members disclosedherein (e.g., clamp member 164, clamp member 165, and/or clamp member194). In some embodiments, the handle assembly 300 may be configured toengage or couple with a single clamp member. In use, the handle assembly300 may be configured to transmit force to the spine through thederotation system as part of a derotation procedure. As illustrated inFIG. 8, the handle assembly 300 can include an elongate member 302 and aplate member 304. The elongate member 302 may be rotatably coupled to(e.g., may be configured to rotate within) the plate member 304. Theelongate member can include a proximal handle-engaging portion 306, afirst leg 310, and a cylindrical body 308 therebetween. The elongatemember 302 may be configured to rotate about longitudinal axis 312. Thehandle-engaging portion 306 can include a circumferential, roundedgroove 314 and/or an angled proximal head 316. As illustrated in FIG. 8,the angled proximal head 316 can include four beveled walls and caninclude, for example, a generally square or rectangular transversecross-section. The handle-engaging portion 306 can be configured tocouple with a handle 318, as illustrated in FIG. 7. In use, the handle318 can be grasped by a user to apply force to the derotation system.

As illustrated in FIG. 8, the first leg can include aneccentrically-shaped member 320 and/or a distal lip 322 extendingtherefrom. The eccentrically-shaped member 320 may have a length, asmeasured along the longitudinal axis 312, which is greater than or equalto a height of a clamp member. The eccentrically-shaped member 320 mayhave a transverse area that is greater than that of the cylindrical body308 of the elongate member 302. When viewed along the longitudinal axis312, the eccentrically-shaped member 320 may have an area that is notequally distributed around the longitudinal axis 312. In someembodiments, the eccentrically-shaped member 320 may have a non-circularand/or non-symmetrical transverse cross-section. For example, theeccentrically-shaped member 320 may be elliptical, ovular, and/oregg-shaped. The eccentrically-shaped member 320 may be referred toherein as a cam member. The distal lip 322 may have a transverse areathat is greater than that of the cylindrical body 308 and/or theeccentrically-shaped member 320. When viewed along the longitudinal axis312, the distal lip 322 may have an area that is not equally distributedaround the longitudinal axis 312. Both the eccentrically-shaped member320 and the distal lip 322 may extend radially beyond the cylindricalbody 308 at some points along a circumference of the cylindrical body308. As illustrated in FIG. 8, the elongate member 302 may generallyinclude a first, unlocked section or portion 324 where the cylindricalbody 308, eccentrically-shaped member 320, and lip 322 are aligned(e.g., flush), and a second, unlocked section or portion 326 where thecylindrical body 308, eccentrically-shaped member 320, and lip 322 arestaggered (e.g., the eccentrically-shaped member 320 and the lip 322 mayeach extend radially outward relative to the cylindrical body 308). Theelongate member 302 may be configured to rotate between a locked andunlocked configuration. In the unlocked configuration, illustrated inFIG. 8, the unlocked portion of the elongate member 302 may be facinginwards (e.g., towards the second leg 330, described herein) and thelocked portion may be facing outwards (e.g., away from the second leg330). In the locked configuration, the unlocked portion of the elongatemember 302 may be facing outwards and the locked portion may be facinginwards.

As illustrated in FIG. 8, the plate member 304 can include a body 328and a second leg 330. The handle assembly 300 may be configured toreceive a clamp member between the first and second legs 310, 330. Thebody 328 of the plate member 304 may be generally flat and/or planar.The body 328 may include a receptacle 332 configured to receive theelongate member 302 therethrough. The second leg 330 may extendperpendicularly or orthogonally from the plate member 304. In someembodiments, the second leg 330 may be affixed or attached to the body328. In other embodiments, the plate member 304 may be a unitarystructure. The second leg 330 may be cylindrical.

In use, a clamp member may be positioned between the first and secondlegs 310, 330 when the handle assembly 300 is in the unlockedconfiguration (e.g., the unlocked portion of the elongate member 302 isfacing inwards). To couple the handle assembly 300 to the clamp member,the elongate member 302 may be rotated to the locked configuration. Theportion of the eccentrically-shaped member 320 that extends radiallybeyond the cylindrical body 308 may rotate into engagement with theclamp member to secure it in a friction fit between the first and secondlegs 310, 330. Additionally, the portion of the lip 322 that extendsradially beyond the cylindrical body 308 may rotate to a position belowthe clamp member, further securing the engagement between the clampmember and the handle assembly 300.

Derotation systems described herein may also include a countertorquedevice 400, as illustrated in FIGS. 7 and 9. The countertorque device400 may be generally flat and/or planar. As illustrated in FIG. 9, thecountertorque device 400 can include an elongate body 402 having firstand second prongs 404, 406 extending distally therefrom. The first andsecond prongs 404, 406 can define a channel or cavity 412 therebetween.The cavity 412 can include a curved section 408 and a linear, straight,and/or flat section 410. As illustrated in FIG. 9, the linear section410 may be distal to the curved section 408. The cavity 412 can alsoinclude a mouth or opening 416 that may be wider than the curved and/orlinear sections 408, 410, as measured between the first and secondprongs 404, 406. A proximal section of the elongate body 402 may includean angular hole 414 passing from a top surface to a bottom surfacethereof. As illustrated in FIG. 9, the angular hole 414 may have fourwalls and can be generally square or rectangular. In other embodiments,the angular hole may have a different number of walls, such as 3, 4, 5,6, 7, or 8, and may be, for example, triangular, rectangular,pentagonal, hexagonal, heptagonal, or octagonal. The angular hole 414may be configured to receive and engage the angular head 316 of thehandle assembly 300. In some embodiments, the elongate body 402 may begenerally hollow. For example, as illustrated in FIG. 9, the elongatebody 402 may include an elongate hole 418 passing from the top surfaceto the bottom surface thereof.

In use, a derotation tower may be positioned between first and secondprongs 404, 406 and within in the cavity 412, as illustrated in FIG. 7.The flat section 410 of the cavity may align with flat section(s) on thederotation towers. The countertorque device 400 may be grasped by a userto prevent a moment from being transferred to an overall constructand/or patient

Some embodiments herein are directed to methods of installing thederotation towers and systems described herein. These methods caninclude providing a plurality of anchor members and derotation towersand/or engaging one or more derotation towers with one or more anchormembers as described herein. In some embodiments, each derotation towercan be engaged with a separate and/or different anchor member (e.g.,each anchor member may be engaged with only one derotation tower). Eachderotation tower can include a proximal derotation tube (e.g., proximalderotation tube 6 or 16) coupled to a distal engagement assembly (e.g.,distal engagement assembly 8, 20, or 44, or rod reducer assembly 80,118, or 140). As described herein, the anchor member can include ananchor or fastener, such as a pedicle screw or hook, and a housing, suchas a tulip head. The anchor or fastener may be at least partiallyreceived within the housing. The anchor member may include an elongaterod associated therewith. For example, the elongate rod may be disposedwithin a channel on the housing. Each derotation tower may be engagedwith a separate anchor member. In some embodiments, a plurality ofderotation towers may be engaged with a plurality of anchor members.

In some embodiments, one or more derotation towers can include a distalengagement assembly, such as distal engagement assembly 20 or 44, asillustrated in FIGS. 4A-C. As described herein, these assemblies mayinclude an outer sleeve (e.g., outer sleeve 22 or 46) slideably disposedover an inner sleeve (e.g., inner sleeve 24 or 48). As described herein,in these embodiments, the step of engaging the derotation tower with theanchor member can include positioning the inner sleeve around at least aportion of the anchor member (e.g., the housing) and translating theouter sleeve distally.

In some embodiments, one or more derotation towers can include a distalengagement assembly that includes a rod reducer assembly, such as rodreducer assembly 80, 118, or 140, as illustrated in FIGS. 5A-D. In theseembodiments, the derotation tower may be configured to urge an elongaterod into engagement with an anchor member. For example, in embodimentswhere the anchor member includes a housing having a rod-receivingchannel, the derotation tower may be configured to urge the elongate roddistally into the channel. In these embodiments, the step of engaging aplurality of derotation towers with a plurality of anchor members mayinclude pushing or urging at least one elongate rod into engagement withthe anchor members.

In some embodiments, the derotation tower may include a distalengagement assembly that includes rod reducer assembly 80, illustratedin FIGS. 5A-B. As described herein, in these embodiments, the rodreducer assembly 80 may include a connector member 82, a clip reducer 84reversibly coupled with the connector member 82 and comprising areduction member 102 and a distal end 98, and a threaded driver. Thestep of engaging the derotation tower with an anchor member (e.g.,anchor member 28) can include positioning the distal end 98 around atleast a portion of the anchor member (e.g., the housing) and threadingthe threaded driver through the clip reducer 84 to actuate the reductionmember 102.

In some embodiments, the derotation tower may include a distalengagement assembly that includes rod reducer assembly 118, illustratedin FIG. 5C. As described herein, in these embodiments, the rod reducerassembly 118 may include a clip reducer 120 and a threaded driver 122.The clip reducer 120 can include a reduction member 134 and a distal end126. The step of engaging the derotation tower with an anchor member caninclude positioning the distal end 126 around at least a portion of theanchor member (e.g., the housing) and threading the threaded driver 122through the clip reducer 120 to actuate the reduction member 134.

In some embodiments, the derotation tower may include a distalengagement assembly that include rod reducer assembly 140, illustratedin FIG. 5D. As described herein, in these embodiments, the rod reducerassembly 140 may include an inner sleeve 142, an outer sleeve 144slideably disposed over the inner sleeve 142, and a rotatable handle 146configured to actuate the outer sleeve 144. The step of engaging thederotation tower with an anchor member (e.g., anchor member 28) caninclude positioning the distal end 150 around at least a portion of theanchor member (e.g., the housing) and rotating the rotatable handle 146to actuate the outer sleeve 144.

Methods of installing the derotation systems described herein may alsoinclude placing, clamping, and/or securing a first clamp member around afirst group of at least two derotation tubes (e.g., first and secondderotation tubes) of at least two derotation towers (e.g., first andsecond derotation towers) along a first axis, to thereby couple togetherthe derotation tubes. In some embodiments, the first axis may be alongitudinal axis or a latitudinal axis. In other embodiments, the firstaxis may be a medial-lateral or cephalad-caudal (e.g.,superior-inferior) axis. Any combinations of the clamp members describedherein, e.g., clamp member 164, 165, and/or 194, can be used as thefirst clamp member in the derotation systems of the present disclosure.As described herein, the first clamp member may include a first elongatearm coupled to an actuator assembly and a second elongate arm having areceiving portion extending therefrom, wherein the actuator assemblyincludes a threaded rod and a threaded nut. The step of clamping thefirst clamp member around the first group of at least two derotationtubes can include opening the first clamp member by pivoting apart thefirst and second elongate arms, placing the first group of at least twoderotation tubes between the first and second elongate arms, insertingat least a portion of the actuator assembly of the first arm into areceptacle in the receiving portion of the second arm, and threading thenut on the rod to reduce a distance between the first and secondelongate arms at a second end of the first clamp member.

Methods of installing the derotation systems described herein may alsoinclude placing, clamping, and/or securing a second clamp member arounda second group of at least two derotation tubes (e.g., first and thirdderotation tubes) of at least two derotation towers (e.g., first andthird derotation towers) along a second axis, to thereby couple togetherthe derotation tubes. Any combinations of the clamp members describedherein, e.g., clamp member 164, 165, and/or 194, can be used as thesecond clamp member in the derotation systems of the present disclosure.The second clamp member can be placed, clamped, and/or secured aroundthe second group of derotation tubes according to the method describedherein of placing, clamping, and/or securing the first clamp memberaround the first group of derotation tubes. As illustrated in FIG. 1, asecond clamp member may be positioned on a derotation tower distal to afirst clamp member, or vice versa.

In some embodiments, the second axis may be a longitudinal axis or alatitudinal axis. In other embodiments, the second axis may be amedial-lateral or cephalad-caudal (e.g., superior-inferior) axis.Advantageously, the second axis may be skewed relative to the first axis(e.g., the first and second axes would intersect if in the same plane).For example, the first axis can be a longitudinal axis and the secondaxis can be a latitudinal axis, or vice versa. In another example, thefirst axis can be a medial-lateral axis and the second axis can be acephalad-caudal axis, or vice versa. In some embodiments, if in the sameplane, the first and second axes would be perpendicular and/ororthogonal.

In some embodiments, one derotation tube (e.g., a single derotationtower), such as the first derotation tube, may be a member of both thefirst and second groups of derotation tubes. Thus, the first and secondclamp members may overlap on the one derotation tube. Additionally, theone derotation tube may link the first and second groups together toassemble a derotation system, which may be referred to herein as aunified (e.g., interconnected) derotation system construct. In someembodiments, at least two or more derotation tubes (e.g., derotationtowers) in the system can be coupled or clamped to at least two otherderotation towers using at least two different clamp members. In someembodiments, each derotation tower in the system can be coupled orclamped to at least two other derotation towers along two different,skewed axes and using at least two different clamp members.

Some embodiments can include clamping each derotation tower to at leasttwo other derotation towers along first and second axes, respectively,for example, as illustrated in FIG. 1. For example, in a systemincluding at least first, second, and third derotation towers, the firstderotation tower can be coupled or clamped to the second derotationtower along the first axis, and can be coupled or clamped to the thirdderotation tower along the second axis. The first and second axes may beskewed relative to each other. In these embodiments, the step ofclamping each derotation tower to at least two other derotation towerscan include clamping at least two (e.g., first and second) clamp membersaround each derotation tower. The first clamp member may extend alongthe first axis and the second clamp member may extend along the secondaxis. In some embodiments, each derotation tower can be clamped to anadjacent ipsilateral derotation tower and an adjacent contralateralderotation tower. Thus, those skilled in the art may appreciate that thederotation systems of the present disclosure can include any number ofderotation towers and/or clamp members. As illustrated in FIG. 1, forexample, in some embodiments the derotation system can include eightderotation towers and six clamp members.

In use, the derotation towers may be engaged with a plurality of anchormembers along two sides of a patient's spine. Advantageously, eachderotation tower may be clamped to at least one derotation tower on thesame side of the spine (e.g., ipsilaterally) and at least one on theopposite side of the spine (e.g., contralaterally). In some embodiments,each derotation tower may be coupled or clamped to at least two otherderotation towers along two different, skewed axes. Advantageously, thiscan provide the derotation system with stability, as compared to asystem that may only allow coupling of some towers, for example, on asingle side of the spine, and can thereby enable a user to effectivelyapply controlled force during a derotation procedure.

Those skilled in the art may appreciate that the derotation towersand/or systems described herein may be used to treat a spinalirregularity, such as an irregular curvature (e.g., scoliosis), forexample, in a derotation procedure. In a derotation procedure, aderotation system may be installed as described herein along a patient'sspine adjacent to the spinal irregularity. As described herein, thesystem may include a plurality of derotation towers installed along bothsides of the patient's spine and coupled together via clamp memberseither ipsilaterally and/or contralaterally. In some embodiments, thesystem can include a plurality of derotation towers coupled togetherwith clamp members in both medial-lateral and cephalad-caudaldirections.

Methods described herein can optionally include coupling a handleassembly (e.g., handle assembly 300) to one of the first and secondclamp members (e.g., clamp member 164, 165, or 194). As describedherein, handle assembly 300 can include an elongate member 302 rotatablycoupled to a plate member 304, wherein the elongate member 302 caninclude a first leg 310 that can include an eccentrically-shaped member320 and/or a distal lip 322. This step can include positioning the clampmember widthwise between the first and second legs 310, 330 of thehandle assembly 300. For example, the first arm of the clamp member maybe adjacent the first leg of the handle assembly and the second arm maybe adjacent the second leg, or vice versa. In some embodiments, theclamp member, for example, as illustrated in FIG. 6A with respect toclamp member 164, can include a plurality of curved depressions orindentations 192. In these embodiments, the first and second legs 310,330 of the handle assembly 300 may nest within these depressions orindentations 192. Advantageously, this feature may encourage a secureengagement between these components. The step of coupling the handleassembly to the clamp member can also include locking and/or securingthe handle assembly to the clamp member. This step can include rotatingthe first leg, for example, from an unlocked configuration to a lockedconfiguration as described herein, to thereby engage theeccentrically-shaped member 320 with the clamp member. In embodimentsthat include distal lip 322, the step of rotating the first leg 310 canalso include rotating the distal lip 322 towards the second leg 330and/or towards (e.g., under) the clamp member. The clamp member maythereby be retained, held, and/or positioned between the body 328 andthe distal lip 322 of the handle assembly 300.

In some embodiments, a handle (e.g., handle 318) can be coupled to thehandle assembly 300. In some embodiments, this step may be performedprior to coupling the handle assembly 300 to one of the clamp members.For example, this step may be performed prior to locking the handleassembly 300, e.g., prior to rotating the first leg 310 from theunlocked configuration to the locked configuration. In theseembodiments, the step of coupling the handle assembly 300 with thehandle 318 can include inserting at least a portion of the proximalhandle-engaging portion 306 into a socket in the handle. The handle 318can be grasped by a user to apply force to the handle assembly 300.Thus, the step of rotating the first leg 310 can include rotating orturning the handle 318 to apply torque to the first leg 310. In someembodiments, the handle assembly 300 and the handle 318 can be connectedor coupled via a quick-connect coupling. In other embodiments, thehandle 318 can include a compressible member configured to be retainedwithin the circumferential groove 314 on the proximal handle-engagingportion 306.

Methods herein can also include applying force to the handle assembly300, e.g., by applying force to the handle 316, to adjust a position(e.g., angle and/or orientation) of at least one derotation tower. Asthe derotation tower may be coupled to an anchor member, this step canalso include adjusting a position of the anchor member. Advantageously,because multiple (e.g., all) derotation towers may be coupled togetherin the derotation system, force applied to the handle assembly 300 maybe distributed throughout the entire system to adjust a positionthereof. In embodiments where each derotation tower is coupled to atleast two different towers in two different directions, the derotationsystem may advantageously configured to sturdily receive and distributeforce evenly therethrough. In a spinal derotation procedure, a user mayapply force to the handle to adjust and/or correct the curvature and/orrotation of a patient's spine.

Some methods may also include coupling and/or securing the anchor member(e.g., a pedicle screw and/or housing) with a fastener (e.g., a setscrew or locking cap). In these embodiments, the fastener may be passedlongitudinally and/or axially through the derotation tower to the anchormember. A countertorque device (e.g., countertorque device 400) may beengaged with the derotation tower. For example, this may includepositioning the derotation tower within the cavity 412 (e.g., betweenthe first and second prongs 404, 406) of the countertorque device 400.In embodiments where the derotation tower includes one or more flatexterior sections as described herein, this step can include aligningthe flat exterior sections with the linear or straight section 410 ofthe cavity 412. In embodiments where the derotation tower includes aflattened section having two parallel walls, this step can includealigning the two parallel walls with the linear or straight section 410of the cavity 412.

Subsequently, an elongate driver may be passed longitudinally and/oraxially through the derotation tower to engage the fastener. Force maybe applied to the driver while the countertorque device 400 is engagedwith the derotation tower to couple the fastener member to the anchormember (e.g., to thread a set screw into a housing or tulip head). Insome embodiments, an elongate rod may be associated with the anchormember. For example, an elongate rod may be disposed within a channel ona housing of the anchor member. In these embodiments, applying force tothe driver, while the countertorque device 400 is engaged with thederotation tower, may also result in securing the anchor member to theelongate rod and/or securing an angle of the anchor member relative tothe elongate rod. Those skilled in the art may appreciate that thecountertorque device may advantageously allow the driver and fastener torotate while preventing or inhibiting the derotation tower and/or anchormember from rotating.

Some methods may also include disengaging the handle assembly 300 fromthe clamp member. This step can include placing the angled proximal head316 of the handle assembly 300 into the angular hole 414 of thecountertorque device 400 and applying force to the countertorque deviceto unlock the handle assembly 300 by rotating the eccentrically-shapedmember 320 and/or distal lip 322 out of engagement with the clamp member(e.g., to rotate the eccentrically-shaped member 320 from the lockedconfiguration to the unlocked configuration).

Some embodiments herein are directed to a kit that can include anycombination of the devices and components described herein. For example,some embodiments can include a plurality of derotation towers, aplurality of clamp members, a plurality of handle assemblies, and/or aplurality of countertorque devices. Multiple variants of derotationtowers, clamp members, handle assemblies, and/or countertorque devicescan also be included in a single kit. Furthermore, the kit can include avariety of different sizes of each device. The kit can additionallyinclude one or more other devices, tools, and/or materials configuredfor use in conjunction with the derotation system or its components. Forexample, a kit may include one or more handles, fasteners (e.g., pediclescrews or hooks), housings (e.g., tulip heads), elongate rods, setscrews, locking caps and/or drivers. In some embodiments, for example,where the kit does not include a derotation tower configured for rodreduction, the kit may additionally include a rod reducer. In otherembodiments, the kit can include one or more additional instrumentsconfigured for use during the installation procedure, such as a probe,forceps, inserter, retractor, distractor, compressor, and/or rod bender.In yet other embodiments, the kit can include one or more additionalimplants, such as an intervertebral cage, plate, transverse rodconnector, and/or bone graft material. In yet other embodiments, thesystems described above can be used with various fusion devices(spacers, plates, rods) and prosthetic devices.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. A derotation system, comprising: first and secondderotation towers, wherein each derotation tower comprises a proximalderotation tube coupled to a distal engagement assembly that isconfigured to engage an anchor member; a clamp member configured toreceive the first and second derotation towers, the clamp member havingan inner surface including an engagement feature, and the engagementfeature is configured to engage an outer surface of the first or secondderotation tower; and a handle assembly configured to engage the clampmember.
 2. The system of claim 1, wherein each derotation tube comprisesa longitudinal axis and a variable transverse outer surface thereabout.3. The system of claim 2, wherein the variable transverse outer surfacecomprises a plurality of angled surfaces.
 4. The system of claim 2,wherein at least one derotation tube comprises first and secondrotatable members in series along the longitudinal axis.
 5. The systemof claim 2, wherein the variable transverse outer surface comprises aknurled surface.
 6. The system of claim 1, wherein the distal engagementassembly comprises an outer sleeve slideably disposed over an innersleeve, wherein the inner sleeve comprises a distal end configured toengage the anchor member.
 7. The system of claim 6, wherein the outersleeve comprises at least two concave gripping surfaces.
 8. The systemof claim 1, wherein the distal engagement assembly comprises a rodreducer assembly, wherein the rod reducer assembly is configured toreduce a rod engaged with the anchor member.
 9. The system of claim 8,wherein the rod reducer assembly comprises: a connector member; a clipreducer configured to be reversibly coupled with the connector memberand comprising a reduction member and a distal end configured to engagethe anchor member; and a threaded driver configured to actuate thereduction member.
 10. The system of claim 8, wherein the rod reducerassembly comprises: a clip reducer comprising a translatable reductionmember and a distal end configured to engage the anchor member; and athreaded driver configured to actuate the reduction member.
 11. Thesystem of claim 8, wherein the rod reducer assembly comprises an innersleeve comprising a distal end configured to engage the anchor member;an outer sleeve slideably disposed over the inner sleeve and configuredto reduce the rod; and a rotatable handle configured to actuate theouter sleeve.
 12. The system of claim 1, wherein: the clamp membercomprises a first elongate arm coupled to an actuator assembly and asecond elongate arm having a receiving portion extending therefrom,wherein the first and second elongate arms are pivotably coupled at afirst end of the clamp member; and at least a portion of the actuatorassembly of the first elongate arm is configured to be reversiblyreceived within a receptacle in the receiving portion of the secondelongate arm.
 13. The system of claim 12, wherein an inner surface ofeach of the first and second elongate arms comprises a retaining featureselected from the group consisting of a knurled surface, a polymericsurface, and a scalloped surface.
 14. The system of claim 12, whereinthe actuator assembly is pivotably coupled to the first elongate arm.15. The system of claim 12, further comprising a cantilever springcoupled to the first elongate arm and the actuator assembly.
 16. Thesystem of claim 12, wherein the receiving portion extends at an obliqueangle relative to the second elongate arm.
 17. A derotation system,comprising: a plurality of derotation towers, wherein each derotationtower comprises a derotation tube; a plurality of clamp members eachhaving a longitudinal axis, wherein each clamp member is configured toengage at least two derotation tubes, the clamp member having an innersurface including an engagement feature, and the engagement feature isconfigured to engage an outer surface of the plurality of derotationtowers; and a handle assembly configured to engage one of the clampmembers.
 18. The system of claim 17, wherein the handle assemblycomprises an elongate member rotatably coupled to a plate member,wherein: the elongate member comprises a proximal handle-engagingportion, a first leg, and a cylindrical body therebetween; and the platemember comprises a body and a second leg extending orthogonallytherefrom; wherein the handle assembly is configured to receive one ofthe clamp members between the first and second legs.
 19. The system ofclaim 17, further comprising a counter-torque device comprising anelongate body having first and second prongs extending distallytherefrom and defining a cavity therebetween, wherein the cavitycomprises a curved section and a linear section.
 20. A derotation kit,comprising: a plurality of derotation towers, wherein each derotationtower comprises a proximal derotation tube; at least one clamp member,wherein the clamp member is configured to engage at least two derotationtowers, the at least one clamp member having an inner surface includingan engagement feature, and the engagement feature is configured toengage an outer surface of the plurality of derotation towers; at leastone handle assembly, wherein the handle assembly is configured to engageat least one clamp member; and at least one countertorque devices,wherein the countertorque device is configured to engage at least onederotation tower.